# coding: utf-8
# Your code here!

x1, y1, x2, y2 = map(float,input().split())
x = (x2 - x1)
y = (y2 - y1)
s = (x*x + y*y)**(1/2)
print(s) x1, y1, x2, y2 = map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 x = (x2 - x1) x x2 - x1 x2 x1 y = (y2 - y1) y y2 - y1 y2 y1 s = (x*x + y*y)**(1/2) s (x*x + y*y)**(1/2) x*x + y*y x*x x x y*y y y 1/2 1 2 print(s) print s y2 = map(float,input().split()) map(float,input().split()) y2 x2, y2 = map(float,input().split()) map(float,input().split()) x2 y1, x2, y2 = map(float,input().split()) map(float,input().split()) y1 x1, y1, x2, y2 = map(float,input().split()) map(float,input().split()) x1 x = (x2 - x1) x2 - x1 x s = (x*x + y*y)**(1/2) (x*x + y*y)**(1/2) s y = (y2 - y1) y2 - y1 y
# coding: utf-8
# Your code here!

x1, y1, x2, y2 = map(float,input().split())
x = (x2 - x1)
y = (y2 - y1)
s = (x*x + y*y)**(1/2)
print(s)
